Gas-cooled fast reactors - Status of CEA preliminary design studies

作者：Dumaz P^*; Allegre P; Bassi C; Cadiou T; Conti A; Gamier J C; Malo J Y; Tosello A

来源：Nuclear Engineering and Design, 2007, 237(15-17): 1618-1627.

DOI：10.1016/j.nucengdes.2007.03.018

The gas-cooled fast reactor (GFR) is one of the six reactor concepts selected in the frame of the Generation IV initiative. The most significant GFR option is the use of a helium high temperature primary coolant. The helium option is very attractive (chemical inertness, neutron transparency, etc.) but it leads to very specific thermal-hydraulic issues. As far as the reactor core design is concerned, a ceramic fuel concept with a good thermal conductivity has been chosen. The main requirement is to obtain an average exit core temperature of 850 degrees C (energy conversion efficiency) with a maximum fuel temperature of about 1200 degrees C and with a low core pressure drop (in order to ease the decay heat removal). The main core characteristics have been determined for two reactor powers: a medium one (600 MWth) and a large one (2400 MWth). For various reasons, this latter became the CEA reference choice. A consistent set of core parameters has been determined taking into account the different constraints including the thermal-hydraulics. The reference arrangement proposed is based on plate fuel elements. A significant issue for the GFR is the decay heat removal. An innovative approach has been chosen in case of loss of coolant accidents (LOCAs). A "guard containment" enclosing the primary system is used to maintain a medium gas pressure (10 bar) in order to remove the decay heat by low power forced convection systems in the short term and natural convection systems in the long term. This guard containment is not pressurized during normal operations and can be a metallic structure. As far as the energy conversion system is concerned, an indirect-combined cycle has been chosen. The significant advantages of this choice are: a moderate core inlet temperature (400 degrees C instead of 480 degrees C for the direct cycle) and an attractive compactness of the primary system (facilitating the guard containment design). Due to the novelty of these options, a significant effort of components pre-sizing and design calculations has been achieved. Following this effort, a CATHARE model of the reactor system has been made and the calculation of the reactor steady-state confirms the consistency of the overall system pre-sizing. This model has been used for a first transient calculation. Other types of transients have to be analyzed, however, it is thought that the proposed GFR design can reach the safety requirements of Generation IV systems.

• 出版日期2007-9
• 单位中国地震局